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991.
Eishun Tsuchida Teruyuki Komatsu Yasuko Mastukawa Tomoyuki Okada 《Macromolecular Symposia》2002,186(1):1-6
Incorporation of different structured synthetic hemes, 5,10,15,20-tetraphenylporphyrinatoiron(II) derivetives with a covalently linked proximal base [FeP( 1 ) to FeP( 7 )], into human serum albumin (HSA), provides seven types of albumin-heme hybrids (HSA-FeP) with different O2-binding abilities. An HSA host absorbs a maximum of eight FeP molecules in each case. The obtained all HSA-FePs can reversibly bind and release O2 under physiological conditions (in aqueous media, pH 7.3, 37°C) as similar as hemoglobin and myoglobin. The difference in the fence structures did not affect the O2-binding parameters, however the axial histidine coordination significantly increased the O2-binding affinity, which is ascribed to the low O2-dissociation rate constants. The most remarkable effect of the heme structure appeared in the half-lifetime (τ1/2) of the O2-adduct complex. The dioxygenated rHSA-FeP( 4 ) showed an unusually long lifetime (τ1/2: 25 hr at 37°C) which is ca. 13-fold longer than that of rHSA-FeP( 1 ). 相似文献
992.
Recombinant human serum albumin complexed with tetraphenylporphinatoiron(II) derivative, “albumin-heme (rHSA-FeP)”, is a synthetic oxygen (O2)-carrying plasma hemoprotein, which becomes a new class of red blood cell substitute. The UV-vis. absorption and ESR spectroscopy revealed that rHSA-FeP formed six-coordinate nitrosyl complex after exposure of nitric oxide (NO) gas. Although the NO-binding affinity of rHSA-FeP (P1/2NO: 1.7 × 10−6 Torr, pH 7.3, 25°C) is 9-fold higher compared to that of hemoglobin (Hb), the administration of this artificial hemoprotein solution into anesthetized rat does not induce an acute increase in blood pressure (hypertension), which is often observed in Hb-based O2-carriers due to the depletion of NO (endothelial derived relaxing factor). 相似文献
993.
Aniket Raut Haoyan Fang Yu-Chung Lin Shi Fu David Sprouster Ryuichi Shimogawa Anatoly I. Frenkel Chulsung Bae John C. Douglin Jaana Lillojad Kaido Tammeveski Zhiqiao Zeng Stoyan Bliznakov Miriam Rafailovich Dario R. Dekel 《Angewandte Chemie (International ed. in English)》2023,62(37):e202306754
Despite the recent progress in increasing the power generation of Anion-exchange membrane fuel cells (AEMFCs), their durability is still far lower than that of Proton exchange membrane fuel cells (PEMFCs). Using the complementary techniques of X-ray micro-computed tomography (CT), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) spectroscopy, we have identified Pt ion migration as an important factor to explain the decay in performance of AEMFCs. In alkaline media Pt+2 ions are easily formed which then either undergo dissolution into the carbon support or migrate to the membrane. In contrast to PEMFCs, where hydrogen cross over reduces the ions forming a vertical “Pt line” within the membrane, the ions in the AEM are trapped by charged groups within the membrane, leading to disintegration of the membrane and failure. Diffusion of the metal components is still observed when the Pt/C of the cathode is substituted with a FeCo−N−C catalyst, but in this case the Fe and Co ions are not trapped within the membrane, but rather migrate into the anode, thereby increasing the stability of the membrane. 相似文献
994.
Hiyori Komatsu Shiharu Watanabe Shima Ito Kazuhiro Nagasaka Akihiro Nishiguchi Tetsushi Taguchi 《Macromolecular bioscience》2023,23(7):2300097
Adhesives/sealants are used after suturing to prevent leakage of cerebrospinal fluid from an anastomotic site. Commercial adhesives/sealants have been used to close the cerebral dura. However, swelling of the cured adhesives/sealants induces increased intracranial pressure and decreases the strength of the seal. In the present study, tissue adhesive hydrogels with improved swelling property using inclusion complex composed of α-cyclodextrin (αCD) and decyl group (C10)-modified Alaska pollock-derived gelatin (C10-ApGltn) with a high degree of substitution (DS) (>20 mol%) are developed. Viscosity of C10-ApGltn with a high DS solution remarkably decreased by the addition of αCD. The resulting αCD/C10-ApGltn adhesive hydrogel composed of αCD/C10-ApGltn inclusion complexes and poly(ethylene glycol) (PEG)-based crosslinker showed improved swelling property after immersion in saline. Also, the resulting adhesive has a significantly higher burst strength than fibrin-based adhesives and is as strong as a PEG-based adhesive. Quantitative analysis of αCD revealed that the improved swelling property of the resulting adhesive hydrogels is induced by the release of αCD from cured adhesive, and the subsequent assembly of decyl groups in the saline. These results suggest that adhesives developed using the αCD/C10-ApGltn inclusion complex can be useful for closing the cerebral dura mater. 相似文献
995.
Optical Review - Heat-assisted magnetic recording (HAMR) is a promising technology for improving the recording density of hard disk drives. A near-field transducer (NFT), which forms a small light... 相似文献
996.
Yao Jing Prof. Yukihiro Yoshida Prof. Tokutaro Komatsu Prof. Hiroshi Kitagawa 《Angewandte Chemie (International ed. in English)》2023,62(29):e202303778
A 2D-to-2D (2D: two-dimensional) structural transformation accompanying significant bond rearrangement and coordination environment change is demonstrated in a coordination polymer (CP) comprised of copper(II) ions and terephthalate (BDC2−) ligands for the first time. When immersed in water, a free-standing membrane of 2D Cu(BDC)(DMF) ( Cu-1 ; DMF: N,N-dimethylformamide) transforms into 2D Cu(BDC)(H2O)2 ( Cu-2 ) while maintaining its highly oriented layered structure. In the 2D sheet, paddlewheel-type CuII dimers coordinated with four bidentate BDC ligands in a square-planar array in Cu-1 were released to form uniform aqua-bridged CuII chains, which are cross-linked with each other by unidentate BDC ligands, in Cu-2 . The present facile approach to implement the 2D-to-2D transformation accompanied by bond rearrangement, which is characteristic of CPs, leads to a marked increase in in-plane magnetic susceptibility and proton conductivity. In situ experiments in support of theoretical calculations unveiled the energy diagram that governs the unique structural transformation. 相似文献
997.
Haruyuki Okamura Masahiko Minoda Takeshi Fukuda Takeaki Miyamoto Koichi Komatsu 《Macromolecular rapid communications》1999,20(2):37-40
Four samples of C60‐(PS)2, i. e., C60 fullerenes with two low‐polydispersity PS arms at the 1,4‐positions, were studied with respect to their solubility and dispersion state in a PS (polystyrene) matrix by the UV spectroscopic method. C60‐bearing polymers were found to be dispersed, in a blend film or a bulk film of itself, either monomolecularly or in aggregates, depending on the chain length of the polymer moiety and blend composition. 相似文献
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